Sensor characteristics of SPOT satellite

HRV loaded on SPOT 1, 2 and 3 satellites is an array push-broom scanner, and its simple structure is shown in Figure 4-5. There is a plane mirror in the instrument, which reflects the electromagnetic wave radiated from the ground to the mirror group, and then focuses on the CCD array element, and the output end of CCD outputs a time-series video signal. Because the CCD element of the line array is used as the detector, an influence line perpendicular to the flight path can be obtained at the same time in an instant, and a continuous image strip along the track can be obtained in a push-and-sweep manner like a slit camera without using a swinging scanning mirror.

there are two types of HTV on p>Spot satellite: one is multi-spectral HRV, and the linear array detector group in each band consists of 3 CCD elements, and the pixel formed by each element is 2m×2m relative to the ground. Therefore, the image line formed by each line of CCD detectors is 2km×6km (2m×6km) relative to the ground. Each pixel is encoded with 8 bits of brightness. The other is panchromatic HRV, which consists of 6 CCD elements in a row. The total width on the ground is still 6km, so the size of each pixel corresponding to the ground is 1m×1m. The encoding uses the brightness difference between adjacent pixels to compress the data volume. Because the brightness difference between adjacent pixels is very small, only 6bit binary code is needed.